For example, this type of connector is disclosed in Patent Document 1. As shown in FIGS. 14A and 14B, the connector with built-in current sensor (connector) of Patent Document 1 comprises a ferrite bead (core), a hall element (current detection member) and a terminal (contact) fixed to a cable. The cable pierces the inside of the core to extend to the outside of the connector. The current detection member is detectable current which flows in the cable.